L44,45,46 Dysrhythmias

Question 1 of 13

1

Choose the incorrect statement.

Select one of the following:

2% of all people over age 65 in New Zealand have Afib.
People with dysrythmias have a higher risk of mortality from MI, stroke, HF and dementia.
Ventricular arrhythmias are less common than atrial fibrillation.

Explanation

Question 2 of 13

1

The mechanism of arrhythmia can be due to abnormal ❌ firing or abnormal ❌. Abnormal impulse firing can be increased ❌ (where cells ❌ SA node start firing spontaneously) or ❌ activity (where cells contract ❌ despite only being activated once).

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impulse

conduction

automaticity

outside

triggered

twice

Explanation

Question 3 of 13

1

Bradyarrhythmias:
1. Sinus Bradycardia - Slow heart rate <❌ bpm(elderly, athletes).
• Increased vagal tone or stimulation, vomiting, myocardial ischemia or MI, ❌thyroid, hypo❌, increased ❌ pressure. Can be caused by drugs: Beta blockers (slow ❌) and/or non-dihydropyridine calcium channel blockers (slow ❌).
2. Sick Sinus Syndrome -
• A ❌ of bradycardia and tachycardia
• Sinus ❌ dysfunction
• Associated with episodes of ❌ tachyarrhythias
3. Atrio-Ventricular Block - impulses generated in atria are conducted ❌ to ventricles or ❌ partially/totally.

2 and 3 can be caused by ❌

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60

intracranial

hypo

thermia

impulse firing

conduction

combination

node

atrial

slowly

blocked

BBs, CCBs, or digoxin

Explanation

Question 4 of 13

1

Tachyarrhythmias:
1. Atrial flutter - Rapid, ❌ atrial depolarization. Atrial rate: 250-350 bpm. If atrial impulses are conducted to the ❌, it can result in ventricular tachycardia. Since atrial rate is high, AV ❌ may occur to protect ventricles...
2. Atrial fibrillation - Most common sustained arrhythmia. mpulses conduct ❌ across the atria – leading to fibrillation. Atrial rate ❌ bpm. AV node irregularly filters (blocks) atrial impulses, irregular increased ❌ rate occurs. Concern is atrial thrombus formation due to stasis. Clinical Features: Fatigue, palpitation, syncope, worsening ❌.
3. Ventricular Tachycardia - Rate ❌ bpm. '❌ VT' if tachycardia lasts >30 seconds. ECG: wide and rapid ❌ complexes (❌: All QRS complexes are similar, or ❌: QRS complexes change in morphology, amplitude, polarity).
4. Torsades de Pointes (TdP) - Variance of polymorphic VT. Drug causes: Anti-arrhythmics (Class Ia, Class III), phenothiazines, erythromycin. Electrolyte causes: ❌, hypomagnesemia.
5. Ventricular Fibrillation - Chaotic (❌) ventricular arrhythmia. Rate 250-500 bpm. Follows ischemic event, most frequent cause of sudden ❌.
6. Wolf-Parkinson-White Syndrome - Early ventricular depolarization. Congenital defect.

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regular

ventricle

block

irregularly

350-600

ventricular

heart failure

100-250

Sustained

QRS

monomorphic

polymorphic

hypokalemia

irregular

death

Explanation

Question 5 of 13

1

Atrial Fibrillation - Classification:
• ❌ =Only one diagnosed episode
• ❌ = Recurrent episodes that stop on their own in <7 days
• ❌ = Recurrent episodes that last >7 days
• ❌ = Ongoing long-term episode

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First detected

Paroxysmal

Persistent

Permanent

Explanation

Question 6 of 13

1

Select all the options which could be clinical presentations of arrhythmia.

Select one or more of the following:

Cardiac arrest
Loss of consciousness/syncope
Shortness of breath
Anxiety
Palpitations
Asymptomatic/no symptoms
Constipation
Dry cough

Explanation

Question 7 of 13

1

Vaughan Williams Classification of Anti-arrythmics:
• Class I - ❌
• Class Ia: Quinidine, Procainamide, Disopyramide (intermediate block)
• Class Ib: Lidocaine, Mexilitine (fast block)
• Class Ic: Flecainide, Propafenone, Moricizine (slow block)
• Class II - ❌
• Class III - ❌
- Amiodarone, Dronedarone, Sotalol, Ibutilide, Dofetilide
• Class IV - ❌
- Diltiazem, Verapamil

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Sodium channel blockers

Beta adrenergic blockers

Potassium channel blockers

Calcium channel blockers

Explanation

Question 8 of 13

1

Choose the incorrect statement.

Select one of the following:

All sodium channel blockers (Class I) decrease conduction velocity and automaticity, but have different affects on the refractory period.
Beta blockers reduce conduction velocity and automaticity, and increase the refractory period.
Potassium channel blockers only affect refractory period, by increasing it.
Calcium channel blockers reduce conduction velocity and automaticity, and increase the refractory period.

Explanation

Question 9 of 13

1

Diltiazem in patients post-MI with heart failure and flecainide post-MI to suppress ventricular ectopy both decrease mortality.

Select one of the following:

True
False

Explanation

Question 10 of 13

1

Choose the incorrect statement about lidocaine.

Select one of the following:

It is Class Ib.
It decreases depolarization, automaticity, and excitability of the ventricles during systole.
It's onset of action occurs within 30-90 seconds.
It can cause hypotension, arrhythmias, and heart block.
It can cause sedation, dizzy, vision changes, seizures, parasthesia.

Explanation

Question 11 of 13

1

Which cardiac-related drugs are greatly affected by coadministration with Amiodarone?

Select one of the following:

Digoxin, Statins, Warfarin, Dabigatran
Digoxin, ACEis, Warfarin, Rivaroxiban
SSRIs, Dabigatran, Phenytoin
Sulphonylureas and beta blockers

Explanation

Question 12 of 13

1

Treating ventricular arrhythmias:
Non sustained VT, no structural disease -
• ❌ blockers, CCB, Class 1(❌ blockers)
• Catheter ❌

VF or TdP (idiopathic) -
• ❌

Structural disease present -
• Treat ❌ cause
• Catheter ablation or ICD
• ❌ when above fails
• Do not give ❌

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Beta

Na+

ablation

ICD

underlying

Amiodarone

CCBs

Explanation

Question 13 of 13

1

Select all the drug classes that target rhythm control instead of rate.

Select one or more of the following:

Class IV agents/Calcium Channel Blockers
Class II agents/Beta blockers
Amiodarone
Digoxin
Class I agents/Sodium channel blockers
Class III agents/Potassium channel blockers

	Created by Mer Scott over 5 years ago

PHCY310 Quiz on L44,45,46 Dysrhythmias, created by Mer Scott on 20/05/2019.

L44,45,46 Dysrhythmias

Question 1 of 13

Choose the incorrect statement.

Select one of the following:

Explanation

Question 2 of 13

The mechanism of arrhythmia can be due to abnormal ❌ firing or abnormal ❌. Abnormal impulse firing can be increased ❌ (where cells ❌ SA node start firing spontaneously) or ❌ activity (where cells contract ❌ despite only being activated once).

Drag and drop to complete the text.

Explanation

Question 3 of 13

Drag and drop to complete the text.

Explanation

Question 4 of 13

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Explanation

Question 5 of 13

Atrial Fibrillation - Classification: • ❌ =Only one diagnosed episode • ❌ = Recurrent episodes that stop on their own in <7 days • ❌ = Recurrent episodes that last >7 days • ❌ = Ongoing long-term episode

Drag and drop to complete the text.

Explanation

Question 6 of 13

Select all the options which could be clinical presentations of arrhythmia.

Select one or more of the following:

Explanation

Question 7 of 13

Drag and drop to complete the text.

Explanation

Question 8 of 13

Choose the incorrect statement.

Select one of the following:

Explanation

Question 9 of 13

Diltiazem in patients post-MI with heart failure and flecainide post-MI to suppress ventricular ectopy both decrease mortality.

Select one of the following:

Explanation

Question 10 of 13

Choose the incorrect statement about lidocaine.

Select one of the following:

Explanation

Question 11 of 13

Which cardiac-related drugs are greatly affected by coadministration with Amiodarone?

Select one of the following:

Explanation

Question 12 of 13

Treating ventricular arrhythmias: Non sustained VT, no structural disease - • ❌ blockers, CCB, Class 1(❌ blockers) • Catheter ❌ VF or TdP (idiopathic) - • ❌ Structural disease present - • Treat ❌ cause • Catheter ablation or ICD • ❌ when above fails • Do not give ❌

Drag and drop to complete the text.

Explanation

Question 13 of 13

Select all the drug classes that target rhythm control instead of rate.

Select one or more of the following:

Explanation

Atrial Fibrillation - Classification:
• ❌ =Only one diagnosed episode
• ❌ = Recurrent episodes that stop on their own in <7 days
• ❌ = Recurrent episodes that last >7 days
• ❌ = Ongoing long-term episode

Treating ventricular arrhythmias:
Non sustained VT, no structural disease -
• ❌ blockers, CCB, Class 1(❌ blockers)
• Catheter ❌

VF or TdP (idiopathic) -
• ❌

Structural disease present -
• Treat ❌ cause
• Catheter ablation or ICD
• ❌ when above fails
• Do not give ❌